Recording and reproducing apparatus, method of calculating temperature characteristic compensation operation coefficient, and reproducing apparatus

Abstract

A recording and reproducing apparatus is provided, which includes a rotary drive unit, an optical pickup unit, an adjustment unit which compensates for changes in characteristics of the laser light caused by changes in temperature, a temperature detection unit which detects a temperature of the optical pickup unit, an evaluation value generation unit which generates an evaluation value based on reflected light information, and a control unit. The control unit performs a temperature acquisition process, an optimum point adjustment process, a temperature acquisition process for acquiring a detected temperature during spin down, an optimum point search process, and a temperature characteristic compensation operation coefficient calculation process for performing temperature compensation with respect to the adjustment values.

1. A recording and reproducing apparatus comprising:
 a rotary drive unit which drives an optical disc recording medium to rotate; 
 an optical pickup unit which is configured to perform laser light radiation and reflected light detection with respect to the optical disc recording medium for data recording/reading; 
 an adjustment unit which compensates for changes in characteristics of the laser light caused by changes in temperature; 
 a temperature detection unit provided to perform temperature detection of the optical pickup unit; 
 an evaluation value generation unit which generates an evaluation value that becomes an index of reproducing signal quality based on reflected light information obtained from the optical pickup unit; and 
 a control unit which performs 
 a temperature acquisition process during a startup operation for acquiring a detected temperature detected by the temperature detection unit as temperature information during a startup operation, corresponding to the startup operation that is performed as a preparation operation for enabling data reproducing after the optical disc recording medium is loaded; 
 an optimum point adjustment process during a startup operation for sequentially changing adjustment values set in the adjustment unit to different values, searching for an optimum point of the adjustment values based on the result of acquiring an evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set, and controlling the adjustment unit to set the adjustment value as the optimum point; 
 a temperature acquisition process during spin down for acquiring a detected temperature detected by the temperature detection unit as temperature information during spin down as a specified condition, which is predetermined so as to stop the rotation of the optical disc recording medium that is rotated by the rotary drive unit, is satisfied after the startup operation is completed; 
 an optimum point search process during spin down for sequentially changing the adjustment values to the different values as the specified condition is satisfied, and searching for the optimum point of the adjustment values based on the result of acquiring the evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set; and 
 a temperature characteristic compensation operation coefficient calculation process for calculating a temperature characteristic compensation operation coefficient for performing temperature compensation with respect to the adjustment values based on information on the optimum point during startup operation, which is obtained by the temperature information during startup operation and the optimum point adjustment process during startup operation, and information on the optimum point during spin down, which is obtained by the temperature information during spin down and the optimum point search process during spin down. 
 
     
     
       2. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs:
 at a start of the startup operation after the spin down, 
 a temperature acquisition process at the start of the startup operation for acquiring the detected temperature detected by the temperature detection unit as the temperature information at the start of the startup operation; 
 an initial adjustment value calculation process for calculating a startup initial adjustment value based on the temperature information at the start of the startup operation and the temperature characteristic compensation operation coefficient that is calculated by the temperature characteristic compensation operation coefficient calculation process; and 
 an initial adjustment value setting control process for controlling the startup initial adjustment value to be set in the adjustment unit as the initial adjustment value at the start of the startup operation. 
 
     
     
       3. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs:
 during execution of a reproducing operation, 
 a real-time adjustment process for controlling the adjustment value that is increased/decreased on the basis of the optimum point obtained by the calculation to be set in the adjustment unit, acquiring the evaluation value generated by the evaluation value generation unit in a state in which the adjustment value is increased/decreased, and making the adjustment value follow the optimum point by repeating calculation of the optimum point of the acquired evaluation value and the adjustment value based on a specified control operation equation; and 
 a real-time adjustment operation coefficient update process for newly calculating a gain coefficient in the control operation equation based on the temperature characteristic compensation operation coefficient that is calculated by the temperature characteristic compensation operation coefficient calculation process. 
 
     
     
       4. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs control so that the optimum point search operation that is performed by the optimum point adjustment process during startup operation and the optimum point search operation that is performed by the optimum point search process during spin down are performed using the same area on the optical disc recording medium. 
     
     
       5. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs:
 a first determination process for determining whether a difference value between the temperature that is acquired by the temperature acquisition process during startup operation and the temperature that is acquired by the temperature acquisition process during spin down is equal to or larger than a specified value; and 
 the optimum point search process during spin down if it is determined that the difference value of the temperature is equal to or larger than the specified value by the first determination process. 
 
     
     
       6. The recording and reproducing apparatus according to  claim 2 , wherein the control unit performs:
 a coefficient average value calculation process for calculating an average value of the past temperature characteristic compensation operation coefficients calculated by the temperature characteristic compensation operation coefficient calculation process; and 
 in the initial adjustment value calculation process, 
 calculation of the startup initial adjustment value based on the temperature information at the start of the startup operation and the temperature characteristic compensation operation coefficient as the average value that is calculated by the coefficient average value calculation process. 
 
     
     
       7. The recording and reproducing apparatus according to  claim 1 , wherein the adjustment unit performs an adjustment on any one of adjustment items of spherical aberration, focus bias, and tilt. 
     
     
       8. The recording and reproducing apparatus according to  claim 1 , wherein an OPC (Optimum Power Control) is performed in the case where recording on the optical disc recording medium is to be performed; and
 wherein the control unit performs: 
 a temperature acquisition process during OPC for acquiring the detected temperature detected by the temperature detection unit as temperature information during OPC when the OPC is performed; and 
 an optimum point adjustment process during OPC for sequentially changing the adjustment values set in the adjustment unit to different values when the OPC is performed, searching for the optimum point of the adjustment values based on the result of acquiring the evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set, and controlling the adjustment unit to set the adjustment value as the optimum point. 
 
     
     
       9. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs:
 a second determination process for determining whether the number of spin-downs reaches a predetermined number of times; and 
 the optimum point search process during spin down if it is determined by the second determination process that the number of spin-downs reaches the predetermined number of times. 
 
     
     
       10. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs:
 a media kind determination process for determining the media kind of the loaded optical disc recording medium; and 
 storing of the temperature characteristic compensation operation coefficient that is calculated by the temperature characteristic compensation operation coefficient calculation process for each media kind determined by the media kind determination process. 
 
     
     
       11. The recording and reproducing apparatus according to  claim 10 , wherein the control unit determines a CD (Compact Disc), a DVD (Digital Versatile Disc), and a BD (High-Density Optical Disc) from one another in the media kind determination process. 
     
     
       12. The recording and reproducing apparatus according to  claim 10 , wherein the control unit further determines a CD, a DVD, and a BD from one another and determines a write-once type and a rewritable type from each other in the media kind determination process. 
     
     
       13. The recording and reproducing apparatus according to  claim 1 , wherein in the case in which the loaded optical disc recording medium is a multilayer disc having a plurality of recording layers, the control unit stores the temperature characteristic compensation operation coefficient that is calculated by the temperature characteristic compensation operation coefficient calculation process for each of the recording layers. 
     
     
       14. The recording and reproducing apparatus according to  claim 1 , wherein the control unit performs:
 a disc object determination process for determining each object of the loaded optical disc recording medium; and 
 storing of the temperature characteristic compensation operation coefficient that is calculated by the temperature characteristic compensation operation coefficient calculation process for each object that is determined by the disc object determination process. 
 
     
     
       15. A method of calculating a temperature characteristic compensation operation coefficient for an adjustment value of an adjustment unit in a recording and reproducing apparatus which includes a rotary drive unit which drives an optical disc recording medium to rotate, an optical pickup unit which is configured to perform laser light radiation and reflected light detection with respect to the optical disc recording medium for data recording/reading, the adjustment unit which compensates for changes in characteristics of laser light caused by changes in temperature; a temperature detection unit provided to perform temperature detection of the optical pickup unit, and an evaluation value generation unit which generates an evaluation value that becomes an index of reproducing signal quality based on reflected light information obtained from the optical pickup unit, the method comprising the steps of:
 acquiring a temperature detected by the temperature detection unit as temperature information during a startup operation, corresponding to the startup operation that is performed as a preparation operation for enabling data reproducing after the optical disc recording medium is loaded; 
 sequentially changing adjustment values set in the adjustment unit to different values during startup operation, searching for an optimum point of the adjustment values based on the result of acquiring an evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set, and controlling the adjustment unit to set the adjustment value as the optimum point; 
 acquiring a temperature detected by the temperature detection unit as temperature information during spin down as a specified condition, which is predetermined so as to stop the rotation of the optical disc recording medium that is rotated by the rotary drive unit, which is satisfied after the startup operation is completed; 
 sequentially changing the adjustment values to the different values as the specified condition is satisfied during spin down, and searching for the optimum point of the adjustment values based on the result of acquiring the evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set; and 
 calculating a temperature characteristic compensation operation coefficient for performing temperature compensation with respect to the adjustment values based on information on the optimum point during startup operation, which is obtained by the temperature information during startup operation and the optimum point adjustment process during startup operation, and information on the optimum point during spin down, which is obtained by the temperature information during spin down and the optimum point search process during spin down. 
 
     
     
       16. A reproducing apparatus comprising:
 a rotary drive unit which drives an optical disc recording medium to rotate; 
 an optical pickup unit which is configured to perform laser light radiation and reflected light detection with respect to the optical disc recording medium for data reading; 
 an adjustment unit which compensates for changes in characteristics of the laser light caused by changes in temperature; 
 a temperature detection unit provided to perform temperature detection of the optical pickup unit; 
 an evaluation value generation unit which generates an evaluation value that becomes an index of reproducing signal quality based on reflected light information obtained from the optical pickup unit; and 
 a control unit which performs 
 a temperature acquisition process during a startup operation for acquiring a detected temperature detected by the temperature detection unit as temperature information during a startup operation, corresponding to the startup operation that is performed as a preparation operation for enabling data reproducing after the optical disc recording medium is loaded; 
 an optimum point adjustment process during a startup operation for sequentially changing adjustment values set in the adjustment unit to different values, searching for an optimum point of the adjustment values based on the result of acquiring an evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set, and controlling the adjustment unit to set the adjustment value as the optimum point; 
 a temperature acquisition process during spin down for acquiring a detected temperature detected by the temperature detection unit as temperature information during spin down as a specified condition, which is predetermined so as to stop the rotation of the optical disc recording medium that is rotated by the rotary drive unit, which is satisfied after the startup operation is completed; 
 an optimum point search process during spin down for sequentially changing the adjustment values to the different values as the specified condition is satisfied, and searching for the optimum point of the adjustment values based on the result of acquiring the evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set; and 
 a temperature characteristic compensation operation coefficient calculation process for calculating a temperature characteristic compensation operation coefficient for performing temperature compensation with respect to the adjustment values based on information on the optimum point during startup operation, which is obtained by the temperature information during startup operation and the optimum point adjustment process during startup operation, and information on the optimum point during spin down, which is obtained by the temperature information during spin down and the optimum point search process during spin down. 
 
     
     
       17. A method of calculating a temperature characteristic compensation operation coefficient for an adjustment value of an adjustment unit in a reproducing apparatus which includes a rotary drive unit which drives an optical disc recording medium to rotate, an optical pickup unit which is configured to perform laser light radiation and reflected light detection with respect to the optical disc recording medium for data reading, the adjustment unit which compensates for changes in characteristics of the laser light caused by changes in temperature, a temperature detection unit provided to perform temperature detection of the optical pickup unit, and an evaluation value generation unit which generates an evaluation value that becomes an index of reproducing signal quality based on reflected light information obtained from the optical pickup unit, the method comprising the steps of:
 acquiring a temperature detected by the temperature detection unit as temperature information during a startup operation, corresponding to the startup operation that is performed as a preparation operation for enabling data reproducing after the optical disc recording medium is loaded; 
 sequentially changing adjustment values set in the adjustment unit to different values during startup operation, searching for an optimum point of the adjustment values based on the result of acquiring an evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set, and controlling the adjustment unit to set the adjustment value as the optimum point; 
 acquiring a detected temperature detected by the temperature detection unit as temperature information during spin down as a specified condition, which is predetermined so as to stop the rotation of the optical disc recording medium that is rotated by the rotary drive unit, which is satisfied after the startup operation is completed; 
 sequentially changing the adjustment values to the different values as the specified condition is satisfied during spin down, and searching for the optimum point of the adjustment values based on the result of acquiring the evaluation value that is generated by the evaluation value generation unit under the condition that the respective adjustment values are set; and 
 calculating a temperature characteristic compensation operation coefficient for performing temperature compensation with respect to the adjustment values based on information on the optimum point during startup operation, which is obtained by the temperature information during startup operation and the optimum point adjustment process during startup operation, and information on the optimum point during spin down, which is obtained by the temperature information during spin down and the optimum point search process during spin down.